In Part 1 of this this series David asked a question:
“Knowing what you know now does the purchase of the three Uzukuri look like a good investment or do you think you could have made home made ones?”
When I first learned of these tools and saw the resultant finish, I knew it was a technique that I wanted to explore. So to that end I began experimenting with materials that I had on hand to try to replicate the function of the actual uzukuri. I also tried to source the actual materials from which to manufacture my own. In the end I made my own version using broomcorn from a cheap broom. Which worked as an acceptable substitute for the “rough” version of the proper tool. To simulate the “medium’ and “fine” versions I employed varying grades of synthetic scuffing/buffing pads. Those pads can be rolled, wadded and folded as needed.
With those substitute tools in hand I began to experiment further to discover the possibilities of this technique. I quickly learned that I was quite fond of the surface that was possible. I also immediately knew that it was something that I would be employing quite a bit in my future work.
I don’t buy a lot of tools. However, I will spend the money if the tool is something that I know I’ll use quite a bit or I can’t reasonable make on my own. So I splurged and bought the three proper uzukuri. That being said. If you think you may only use this technique once in a blue moon or just wanting to experiment, then the previously mentioned broomcorn version and buffing pads will serve you quite well.
Continuing with my experimentation/practice.
All of the things I discussed in Part 1 continue to hold true and are working very well. There are a couple of areas that have given me difficulty though.
One area is that which has a wide expanse of early (soft) wood. In those areas the “rough” uzukuri tends to leave deep grooves. Most, not all, of which can be removed with the “medium” uzukuri but it takes quite a lot of work. I needed a better way. First I experimented with sandpaper for this. Sandpaper works, but is hard to control given the relatively small area that I’m working in. Next I tried using a gouge. That actually worked well, but resulted in an uneven surface within the softwood which took just as much effort to correct as the original deep grooves.
My day job has me on the manufacturing floor just about every day. The primary operation taking place is welding. We work with both steel and aluminum for the products that we produce. It’s the aluminum welding operation that gave me the answer for removing the grooves from the large areas of soft wood. The last operation when creating an aluminum weld is to clean it with a stiff wire brush. These brushes come in several sizes. The most popular size on the shop floor is about the size of a toothbrush. These come in both brass and stainless steel. This brush looked like it might work.
I picked up a couple of stainless steel brushes from the welding supply aisle at the Home Depot and toted them back to the shop. Sure enough the brush worked like a charm. Abrasive enough to speed up the removal of wood, yet fine enough to leave a relatively smooth surface. I find the brush to be very controllable and it also conforms well to established grain pattern raised by the “rough” uzukuri. That problem is solved.
The other area of difficulty is end grain. None of the three uzukuri are very effective on end grain. For the most part this is not that big a deal. Generally the projects that I build have very little exposed end grain. But I still wanted to find a solution to extending the surface treatment to the end grain.
The wire brush works quite well on fine grain examples. For the more open grain pieces, I found the best solution to be a small round file. A couple of light strokes with the file, in the soft wood only, is all that is needed.
The final touch for the end grain is a light rub with a buffing pad.
Another trick, I learned strictly by happenstance. It’s been abnormally hot the last few days. 90F hot. So while working on one of the sides some sweat dripped onto the work piece. The wetted area reacted very differently than the dry area. The wet area caused the uzukuri to be far more aggressive in the soft early wood. So a little experimenting and I discovered that by wetting the wood I could remove the early wood to a greater depth without any significant change to the harder late wood. The result is a much more defined grain pattern. The downside is that I’ll need to let the wetted areas dry for a day or so before continuing with the “medium” and “fine” uzukuri. You can’t burnish wet wood. The photo below shows the result of wetting and the “rough” uzukuri.
A couple of photos looking down the sides of the Japanese toolbox that I’m building.
I also experimented with a deeper pattern applied to a piece with somewhat open grain. After first using the “rough’ uzukuri, I used the gouge to deepen the groove in the soft wood areas. One long, very shallow cut with the gouge was all that was needed. I then followed up with the “medium” and “fine” uzukuri. Much more dramatic in both appearance and texture.
In the next part I’ll discuss how this technique responds to oil finishes.